Explosive powder-driven tool for setting anchoring members

ABSTRACT

In an explosive powder-driven tool for setting bolts and the like in a hard receiving material, a barrel is axially displaceable within an opening in the tool housing and a piston is axially displaceable within the bore in the barrel. A slot extending in the axial direction is provided in the barrel and a spring-biased stop member is pivotally mounted in a recess in the housing for displacement into the slot so that the piston can be secured against axial movement relative to the housing while the barrel is moved in the axial direction. The recess also opens to the exterior of the tool housing and the barrel affords a seal for the recess when the tool is arranged in the firing position. Accordingly, when an anchoring member is fired from the tool, any gases developed which pass from the barrel into the recess containing the stop member will flow out of the tool because the recess is open to the exterior of the tool.

United States Patent v [ll] 3,820,703 Rangger June 28, 1974 EXPLOSIVE POWDER-DRIVEN TOOL FOR SETTING ANCHORING MEMBERS Primary Examiner-Granville Y. Custer, Jr.

[75] Inventor: Herbert Rangger, Frastanz, Austria Attorney Agent or firm-Town McGeady and Stanger [73] Assignee: Hilti Aktiengesellschaft,

Fuerstentum, Liechtenstein [57] ABSTRACT [22] Flled: 1972 In an explosive powder-driven tool for setting bolts [21] Appl. No.: 304,639 and the like in a hard receiving material, a barrel is ax ially displaceable within an opening in the tool housing and a piston is axially displaceable within the bore Foreign Application Data in the barrel. A slot extending in the axial direction is Nov. 15, 19.71 Germany 2156697 provided in the barrel and a spring-biased stop memher is pivotally mounted in a recess in the housing for [52] U.S. Cl. 227/10 displacement into the slot so that the piston can be se- [5l] Int. Cl. B25c 1/14 cured against axial movement relative to the housing [58] Field of Search 227/8, 10, 11 while the barrel is moved in the axial direction. The recess also opens to the exterior of the tool housing [56] References Cited and the barrel affords a seal for the recess when the UNITED STATES PATENTS tool is arranged in the firing position. Accordingly, 3,549,074 12/1970 Brunelle 227/10 when anchoring member is fired from the tool any gases developed which pass from the barrel into the 3,563,439 2/1971 Pomero y recess contaInIng the stop member wIll flow out of the 3,565,313 2/l97l Seghezzi et al..

3,659,768 5/1972 Brunelle 227/10 tool because the recess is open to the exterior of the FOREIGN PATENTS OR APPLICATIONS 1,923.91 I I l/1970 Germany 227/10 7 Claims, 2 aw ng Figures EXPLOSIVE POWDER-DRIVEN TOOL FOR SETTING ANCHORING MEMBERS SUMMARY OF THE INVENTION The present invention is directed to an explosive powder-driven tool for setting anchoring members, such as bolts, studs and the like into a hard receiving material and, more particularly, it is directed to the arrangement of a stop member pivotally mounted within a recess in the tool housing so that the stop member can extend into a slot formed in the barrel during a certain part of the operating cycle of the tool.

Various types of tools for setting anchoring members which include axially displaceable barrels are known. Due to the axial displaceability of the barrehafter a tool has been fired, it is possible to return the driving piston from the forward end of the barrel to its rearward end so that it is in the firing position. Accordingly, known tools of this type have used stops having a fixed position relative to the housing and positionable through a longitudinal slot into the path of the piston forreturning the piston to the firing position.

When such a tool has been fired, the piston is displaced into the forward end of the barrel and for reestablishing the tool in the firing position, the barrel is pulled forwardly, that is in the firing direction, and the stop extends through the longitudinal slot in the barrel and secures the piston against movement relative to the tool housing while the barrel moves forwardly. Accordingly, the action of the stop causes the piston to be displaced into the rearward end of the barrel. After the barrel has been pulled forwardly to the required extent, it is again pushed rearwardly into the tool housing in the direction opposite to the driving direction and, with the piston located in the rearward end of the barrel, the tool is again set in the firing position.

In Swiss Pat. No. 480,l4l a stop similar to the type described above is disclosed. The stop is a pivotally mounted two-armed member, one arm of which extends through a longitudinal slot in the barrel into the path of the piston. When the tool is in the firing position, the two-armed stop is pivoted within a recess in the tool housing so that the arm intended to extend into the path of the piston is held in the recess out of the path of the piston.

This previously known stop arrangement has the disadvantage that, during each firing operation, it is fully exposed to the gases generated when an explosive powder charge is ignited and, as a result, experiences a certain fouling during each firing operation, which after a period of time greatly limits its effectiveness. Further, the recess in the housing for the stop forms a trap for residues from the explosion used in driving the piston for inserting an anchoring member. Cleaning of the stop and its recess for removal of any residues resulting from the firing action is possible only after a timeconsuming disassembly of the tool.

Therefore, it is the primary object of the present invention to provide a tool of the above-mentioned type in which' the disadvantages mentioned above can be avoided.

In accordance with the present invention, the recess for the stop is arranged so that it opens to the outside or exterior of the tool housing and, when the tool is in the firing position, the barrel forms a closure for the recess.

Since the opening from the recess to the longitudinal slot is closed when the tool is in the firing position, the explosive powder gases generated upon firing are prevented from passing into the recess and fouling the stop. If, despite the closure provided for the recess by the barrel, small amounts of gases should enter the recess due to the clearance required for the operation of the tool, that is between the tool housing and the barrel, the gases can pass through the recess to the exterior of the tool because of its open construction and the accumulation of residues within the recess will be prevented. The opening of the recess to the exterior of the tool can be provided either in the form of individual outflow channels or by arranging the recess so that it is completely open to the outside. When the recess is designed so that it is opened to the outside of the tool, it has the further advantage that the stop member is easily accessible, which is particularly advantageous for the disassembly of the barrel or the piston, since such disassembly can be performed without using any special tools.

When the tool is reset in the firing position the stop member must be arranged so that it pivots back into the recess in the housing for clearing the path of the piston so that it can move forwardly within the bore in the barrel for driving anchoring members into a receiving ma terial. For pivoting the stop member completely into the recess, the forward end of the slot in the barrel is designed as a cam surface for engaging and displacing the stop member against a spring-biasing action. When the barrel is moved rearwardly by the required distance employed for safety reasons prior to firing well as to establish it in the firing position, the cam surface causes the stop member to pivot into the recess in the housing.

In arranging the tool so that the stop member is dis placed into the recess in the housing, it is also preferable to position the forward portion of the barrel over the opening from the recess through which the stop moves in entering the slot in the barrel. The opening from the recess for permitting the stop member to enter into the bore within the barrel can be produced in a simple manner so that the forward end of the barrel can easily afford a seal or closure forthe opening from the recess in the housing into the slot in the barrel.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view, partly in section, of a tool for driving anchoring members embodying the present invention, and with the tool arranged in the firing position; and

FIG. 2 is a detail view of a portion of the tool shown in FIG. 1, however, with the tool arranged in the fired position. I

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 a tool for driving anchoring members, such as bolts, studs and the like, into a hard receiving material, is shown in the firing position. The tool 1 includes a housing 6 having a handle 2 fixed to the rearward end of the housing and a trigger 3 mounted in the handle for actuating a striker 4 in a known manner so that it can ignite a cartridge 5. The housing 6 forms an opening within which a barrel 7 is mounted for axial displacement and the cartridge is located within a cartridge magazine 8 situated at the rearward end of the barrel, that is its end adjacent the handle 2. Axially displaceably mounted within the barrel is a piston 9 which is driven forwardly toward the muzzle end of the barrel when the cartridge 5 is ignited and gases are generated. Located at the muzzle end of the barrel 7 is a standplate 10 which serves as a guide both for the piston shank 9a of the piston and also for the anchoring members driven into the receiving material by the piston. In addition to the piston shank 9a, the piston also includes a shoulder 91) adjacent the rearward end of the piston shank and a piston head 90 at the rearward end of the piston. In the firing position shown in FIG. 1 the piston head 90 seats against the rearward end of the barrel immediately forward of the cartridge magazine 8. The pis ton head 9c has a diameter greater than the diameter of the piston shank and rides along the surface of the bore within the barrel 7. When the piston is driven forwardly, if excess energy is developed, the forward movement of the piston is stopped when the shoulder 9b engages a correspondingly shaped surface 10a at the rearward end of the standplate 10.

When an anchoring member has been driven from the tool 1 by the piston 9, the piston is displaced into the forward end of the barrel 7 and the major portion of its piston shank 9a extends through the standplate 10. To return the piston 9 so that its head 90 is at the rearward end of the barrel 7 adjacent the cartridge magazine 8, that is to reset the tool into the firing position, the standplate l0 and the barrel 7 which is attached to the standplate is pulled forwardly in the driving or firing direction,.preferably manually. The barrel has a longitudinally or axially extending slot 7a extending for a substantial portion of its length between its rearward and forward ends. At the forward end of the housing, in alignment with the slot 7a in .the barrel,

is a recess II which extends through the housing 6 so that itis open both to the slot 7a and to the exterior of the tool. A stop member 14 is pivotally mounted on a pin 13 within the recess I1 and a spring 12 resiliently biases the stop member for movement in a counterclockwise direction as viewed in FIG. 1. The stop member has a pair of angularly spaced arms 14a, 14b with j the arms facing in the opposite direction to the firing direction of the tool. As can be seen in FIG. 1, when'the tool is in the firing position, the forward end of the barrel 7 extends over and forms a closure or seal for the side of the recess 11 which opens toward the slot 7a in the barrel. When the barrel is pulled forwardly its forward end is displaced axially from above the recess 11 and the spring 12 causes the arm 14a of the stop member 14 to pivot upwardly through the slot 7a in the barrel so that the free end of the arm 14a extends into the path of the piston 9 through the bore in the barrel, as can be seen in FIG. 2.

As illustrated in FIG. 2, the surface of the housing defining the recessll has a portion 6a which limits the pivoting movement of the arm 14b of the stop member. Due to the cooperation of the arm 14b and the portion 6a of the housing surface, the rotary movement of the stop member 14 is limited so that the other arm 14a extends into the bore of the barrel whereby it is disposed in the path of the diameter of head but does not extend inwardly sufficiently to contact the increased diameter portion of the piston shank 9a located adjacent the piston head.

With the arm 14a of the stop member 14 extending into the bore of the barrel and engaging the piston head 90 of the piston, when the barrel is continued to be pulled forwardly from the housing, there is no relative movement between the piston 9 and the housing 6 and the piston is displaced relative to the barrel so that its head 9c contacts the rearward end of the barrel 7. Subsequently, when'the barrel 7 and the standplate 10 are pushed in the direction opposite to the driving or firing directio ma cam surface 7!) at the forward end of the slot 7a in the barrel contacts'the arm 14a of the stop member and causes it to pivot about the pin 13 and against the biasing action of the spring 12 until the arm 14a is completely contained within the recess 11. The piston 9, in frictional engagement with the barrel 7 by means'of a friction ring 15, is thus returned along with the barrel into the firing position, shown in FIG. 1. As the barrel moves rearwardly into the opening in the housing, its forward end moves over the upper end of the recess 11 and forms a seal or closure for the recess.

In the drawing, the recess 11 in the tool 1 is arranged so that it forms the opening through which the stop extends into the path of the piston within the bore in the barrel. Additionally, as indicated above, the recess 11 containing the stop member 14 is open to the exterior of the tool so that any minor amounts of explosive gases entering the recess 11 in spite of the seal provided by the barrel cooperating with the housing, can pass through the recess and flow unhindered outside of the tool-so that no deposits or residue form within the recess 11.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

I claim:

1. An explosive powder-driven tool for setting bolts and similar'anchoring members in a hard receiving material, includes a housing having a forward end and a rearward end and an opening extending through said housing from its forward end towards its rearward end, an axially elongated barrel having a muzzle end and a rearward end mounted in the opening in said housing and being axially displaceable relative to said housing, said barrel forming an axially extending bore and an elongated axially extending slot formed in said barrel with said slot extending between the bore and the outer surface of said barrel, an axially elongated driving piston having a forward end and a rearward end positioned within the bore in said barrel, said piston being axially displaceable through said bore, said tool having a firing position and a fired position and in the firing position said barrel having its rearward end located at the rearward end of the opening in said housing and said barrel being forwardly displaceable through the opening in said housing for returning said tool to the firing position, in the firing position said piston having its rearward end located at the rearward end of said barrel and being axially displaceable toward the muzzle end thereof to the fired position, said housing having a recess adjacent its forward end and said recess arranged in communication with the opening through said housing, a stop member pivotally mounted in said recess in said housing and being displaceable into said slot in said barrel. wherein the improvement comprises that said recess in said housing extends outwardly to the exterior surface of said housing and is open to the outside of said housing so that a passageway is formed through said housing by said recess from the opening through said housing to the exterior surface of said housing, the forward end of said barrel forwardly of the forward end of said slot is in surface contact with the surface of the opening in said housing, and in the firing position of said tool said recess in said housing being spaced forwardly of the forward end of said slot in said barrel and the forward end of said barrel extending forwardly of the forward end of said slot forming a seal between said recess and said bore within said barrel.

2. 'An explosive powder-driven tool, as set forth in claim 1, wherein the forward end of said slot in said barrel is formed as a cam surface for pivotally displacing said stop member from said slot into said recess in said housing when said barrel is displaced rearwardly into the firing position.

3. An explosive powder-driven tool, as set forth in claim 1, wherein spring means are associated with said stop for biasing said stop into said slot in said barrel when said barrel is moved forwardly relative to said housing and said slot uncovers said recess therein.

4. An explosive powder-driven tool, as set forth in claim 3, wherein said piston having a piston head at its rearward end and a piston shank extending forwardly from said piston head, said piston head having a diameter larger than said piston shank.

5. An explosive powder-driven tool for setting bolts and similar anchoring members in a hard receiving material includes a housing having a forward end and a rearward end and an opening extending through said housing from its forward end toward its rearward end, an axially elongated barrel having a muzzle end and a rearward end mounted in the opening in said housing and being axially displaceable relative to said housing, said barrel forming an axially extending bore and an elongated slot formed in said barrel with said slot extending between the bore and the outer surface of said barrel, an axially elongated driving piston having a forward end and a rearward end positioned within the bore in said barrel, said piston being axially displaceable through said bore, said tool having a firing position and a fired position and in the firing position said barrel having its rearward end located at the rearward end of the opening in said housing and said barrel being forwardly displaceable through the opening in said housing for returning said tool to the firing position, in the firing position said piston having its rearward end located at the rearward end of said barrel and being axially displaceable toward the muzzle end thereof to the fired position, said housing having a recess adjacent its forward end and said recess arranged in communication with the opening through :said housing, a stop member pivotally mounted in said recess in said housing and being displaceable into said slot in said barrel, wherein the improvement comprises that said recess in said housing extends outwardly to the exterior surface of said housing and is open to the outside of said housing, in the firing position of said tool said recess in said housing being spaced forwardly of the forward end of said slot in said barrel and the forward end of said barrel extending forwardly of the forward end of said slot forming a seal between said recess and said bore within said barrel, the forward end of said barrel forwardly of said slot therein forms a covering for the opening from said recess into the opening through said housing when said tool is in the firing position, spring means associated with said stop for biasing said stop into said slot in said barrel when said barrel is moved forwardly relative to said housing and uncovers said recess therein, said piston having a piston head at. its rearward end and a piston shank extending forwardly from said piston head, said piston head having a diameter larger than said piston shank, and said stop member having a pair of angularly spaced arms with one of said arms arranged to extend into said bore in said barrel inwardly of the outside diameter of said piston head so that it forms a stop for engagement with the forward end of said piston head.

6. An explosive powder-driven tool, as set forth in claim 5, wherein the surface of said recess formed by said housing is shaped to provide a stop surface for the other one of said arms of said stop member so that when said stop member is resiliently biased into the slot the stop surface of said housing prevents said stop member from extending into contact with said piston shank of said piston while affording contact with said piston head.

7. An explosive powder-driven tool, as set forth in claim 6, wherein a friction ring encircles and is seated in said piston head and is disposed in contact with the surface of said bore in said barrel for providing frictional contact wherewith. 

1. An explosive powder-driven tool for setting bolts and similar anchoring members in a hard receiving material, includes a housing having a forward end and a rearward end and an opening extending through said housing from its forward end towards its rearward end, an axially elongated barrel having a muzzle end and a rearward end mounted in the opening in said housing and being axially displaceable relative to said housing, said barrel forming an axially extending bore and an elongated axially extending slot formed in said barrel with said slot extending between the bore and the outer surface of said barrel, an axially elongated driving piston having a forward end and a rearward end positioned within the bore in said barrel, said piston being axially displaceable through said bore, said tool having a firing position and a fired position and in the firing position said barrel having its rearward end located at the rearward end of the opening in said housing and said barrel being forwardly displaceable through the opening in said housing for returning said tool to the firing position, in the firing position said piston having its rearward end located at the rearward end of said barrel and being axially displaceable toward the muzzle end thereof to the fired position, said housing having a recess adjacent its forward end and said recess arranged in communication with the opening through said housing, a stop member pivotally mounted in said recess in said housing and being displaceable into said slot in said barrel, wherein the improvement comprises that said recess in said housing extends outwardly to the exterior surface of said housing and is open to the outside of said housing so that a passageway is formed through said housing by said recess from the opening through said housing to the exterior surface of said housing, the forward end of said barrel forwardly of the forward end of saId slot is in surface contact with the surface of the opening in said housing, and in the firing position of said tool said recess in said housing being spaced forwardly of the forward end of said slot in said barrel and the forward end of said barrel extending forwardly of the forward end of said slot forming a seal between said recess and said bore within said barrel.
 2. An explosive powder-driven tool, as set forth in claim 1, wherein the forward end of said slot in said barrel is formed as a cam surface for pivotally displacing said stop member from said slot into said recess in said housing when said barrel is displaced rearwardly into the firing position.
 3. An explosive powder-driven tool, as set forth in claim 1, wherein spring means are associated with said stop for biasing said stop into said slot in said barrel when said barrel is moved forwardly relative to said housing and said slot uncovers said recess therein.
 4. An explosive powder-driven tool, as set forth in claim 3, wherein said piston having a piston head at its rearward end and a piston shank extending forwardly from said piston head, said piston head having a diameter larger than said piston shank.
 5. An explosive powder-driven tool for setting bolts and similar anchoring members in a hard receiving material includes a housing having a forward end and a rearward end and an opening extending through said housing from its forward end toward its rearward end, an axially elongated barrel having a muzzle end and a rearward end mounted in the opening in said housing and being axially displaceable relative to said housing, said barrel forming an axially extending bore and an elongated slot formed in said barrel with said slot extending between the bore and the outer surface of said barrel, an axially elongated driving piston having a forward end and a rearward end positioned within the bore in said barrel, said piston being axially displaceable through said bore, said tool having a firing position and a fired position and in the firing position said barrel having its rearward end located at the rearward end of the opening in said housing and said barrel being forwardly displaceable through the opening in said housing for returning said tool to the firing position, in the firing position said piston having its rearward end located at the rearward end of said barrel and being axially displaceable toward the muzzle end thereof to the fired position, said housing having a recess adjacent its forward end and said recess arranged in communication with the opening through said housing, a stop member pivotally mounted in said recess in said housing and being displaceable into said slot in said barrel, wherein the improvement comprises that said recess in said housing extends outwardly to the exterior surface of said housing and is open to the outside of said housing, in the firing position of said tool said recess in said housing being spaced forwardly of the forward end of said slot in said barrel and the forward end of said barrel extending forwardly of the forward end of said slot forming a seal between said recess and said bore within said barrel, the forward end of said barrel forwardly of said slot therein forms a covering for the opening from said recess into the opening through said housing when said tool is in the firing position, spring means associated with said stop for biasing said stop into said slot in said barrel when said barrel is moved forwardly relative to said housing and uncovers said recess therein, said piston having a piston head at its rearward end and a piston shank extending forwardly from said piston head, said piston head having a diameter larger than said piston shank, and said stop member having a pair of angularly spaced arms with one of said arms arranged to extend into said bore in said barrel inwardly of the outside diameter of said piston head so that it forms a stop for engagement with the forward end of said piston head.
 6. An explosive powder-driven tool, As set forth in claim 5, wherein the surface of said recess formed by said housing is shaped to provide a stop surface for the other one of said arms of said stop member so that when said stop member is resiliently biased into the slot the stop surface of said housing prevents said stop member from extending into contact with said piston shank of said piston while affording contact with said piston head.
 7. An explosive powder-driven tool, as set forth in claim 6, wherein a friction ring encircles and is seated in said piston head and is disposed in contact with the surface of said bore in said barrel for providing frictional contact wherewith. 